Corner reflectors are used with radar systems in a variety of ways such as to align the systems and provide measurements of the effectiveness of the system. They constitute high reflectivity (high radar cross section) targets that can be located in the radar examined field or attached to other targets to assist in location and identification of the targets.
Corner reflectors are used because they reflect incident radiation directly back to the source, independently of the angle of the incidence of the radiation on the reflector.
When a linearly polarized radar source is used, it is desirable that the reflector reflect a cross-polarized signal back to the radar unit when the radar has a cross-polarized channel. One method of increasing the reflected energy from a corner reflector, by causing the incident linearly polarized beam to be reflected in a cross polarized manner, is disclosed in U.S. Pat. No. 3,309,705. That patent discloses a corner reflector having a cross polarizing plate covering the opening in the corner reflector. While this arrangement increases the radar cross section of the reflector it does not provide a uniform strength reflection independent of the angle of incident of the beam but rather produces a high spike of energy if the incident beam is normal to the faceplate. This makes it difficult to obtain reliable measurements when the reflector is being used to align a radar system. Another drawback of the system of U.S. Pat. No. 3,309,705 is that energy is lost when the incident radar waves pass through the depolarizing plate on the way to the reflector and more energy is lost when the reflected wave passes back through the depolarizer. Additionally, the cross polarizing faceplate causes reverberation between the corner reflector and the faceplate.
The present invention is accordingly directed to a corner reflector operative to reflect cross-polarized signals to linearly polarized radar sources which produces uniform reflection independent of the angle of incidence and minimizes the losses within the reflector.